Image reading apparatus and image forming apparatus

ABSTRACT

An image reading apparatus, including point light sources, arranged in a straight line state, configured to output light to light a document, and a light leading member, positioned in front in a light outputting direction of the light output from the point light sources, configured to receive the light incident on a surface of the light leading member, and to lead the received light so as to irradiate along a main scanning direction toward the document. The light leading member includes a positioning unit configured to make a gap between one of the point light sources arranged in a line state and the light leading member the same as a gap between another of the point light sources and the light leading member, and to make an arrangement direction of the point light sources be positioned along a longitudinal direction of the light leading member.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image reading apparatus havingplural point light sources arranged in a straight line state and animage reading apparatus having the light reading apparatus.

2. Description of the Related Art

As an image reading apparatus used for an image forming apparatus suchas a copying machine, one having a structure where plural LEDs (pointlight sources) lighting a document are arranged in a straight line stateis known conventionally. See Japanese Patent Application Laid-OpenPublication Nos. 07-162586 and 10-322521, for example. Furthermore, in acase where plural LEDs are used as light sources, in order to preventthe generation of illuminance ripple (unevenness of illuminationdistribution) in an arrangement direction of the LEDs at an object to belighted, namely the document, a light leading member made of transparentresin, glass, or the like is arranged between the object to be lightedand the point light sources. The light leading member leads lightirradiating from the point light sources and diffusing in a circletoward a surface of the document along a main scanning direction at thetime when the document is read out, so that the light leading member canprevent the generation of the illuminance ripple.

However the inventions disclosed in the above-mentioned Japanese PatentApplication Laid-Open Publications and others have a problem in that thesurface of the document cannot be uniformly illuminated along the mainscanning direction if a distance between the plural LEDs and the lightleading member is not constant.

A state where the surface of the document is not being uniformlyilluminated along the main scanning direction due to the distancebetween the LEDs and the light leading member not being constant isdiscussed with reference to FIG. 1 through FIG. 3. The lighting deviceof this optical reading apparatus, as shown in FIG. 1, includes an LEDarray substrate 102 and a light leading member 103. In the LED arraysubstrate 102, plural LEDs (point light sources) 100 are arranged andfixed on a substrate 101. The light leading member 103 is positioned infront of an outputting direction of light output from the LED 100. TheLED array substrate 102 and the light leading member 103 are attached toa housing member 104.

The light output from the LEDs 100 is led by the light leading member103 so as to be irradiated along the main scanning direction of thedocument D provided on a contact glass 105. Reflection light from thedocument D is read out at a CCD (photoelectric conversion element) via amirror 106 or lens (not shown) so that image information correspondingto the image of the document D can be obtained.

FIG. 2 shows a case where a position relationship between the lightleading member 103 and the LED array substrate 102 is shifted from aproper position. The direction of the shift causes the distance betweenthe LEDs and the light leading member 103 to be not constant. In thiscase, an amount of light, incident on the light leading member 103 afterthe light is output from the LEDs 100 at the position where the distancebetween the light leading member 103 and the LED 100 is short is large.The amount of light, incident on the light leading member 103 after thelight is output from the LEDs 100 at the position where the distancebetween the light leading member 103 and the LED 100 is long is small.Because of this, an amount of light, incident on the document D afterthe light is output from the light leading member 103 at a side wherethe distance between the light leading member 103 and the LED 100 isshort is large. An amount of light incident on the document D after thelights is output from the light leading member 103 at a side where thedistance between the light leading member 103 and the LED 100 is long issmall. Arrows shown in FIG. 2 show light beams incident on the documentD and led by the light leading member 103 after the light beams areoutput from the corresponding LEDs 100. A length of each arrowrepresents an amount of the irradiated light.

FIG. 3 shows a case where a position relationship between the lightleading member 103 and the LED array substrate 102 is shifted from aproper position.

A direction of the shift causes the arrangement direction of the LEDs100 and the longitudinal direction of the light leading member 103 to betwisted. In this case, the light beams output from the LEDs arranged inthe center of the arrangement direction are incident on the lightleading part 103, led by the light leading member 103, and incident onthe document D. However, the light beams output from the LEDs 100positioned at both end sides in the arrangement direction are notincident in the light leading member 103. The document D is not lightedat either end side in a longitudinal direction of the light leadingmember 103.

SUMMARY OF THE INVENTION

Accordingly, it is a general object of the present invention to providea novel and useful image reading apparatus and image forming apparatus.

Another and more specific object of the present invention is to providean image reading apparatus and image forming apparatus whereby pluralpoint light sources equally face the light leading member so that thedocument is uniformly irradiated along the main scanning direction bythe light led by the light leading member after the light is output fromthe point light source.

The above object of the present invention is achieved by an imagereading apparatus, including:

a plurality of point light sources, arranged in a straight line state,configured to output light for lighting a document situated on a contactglass from a lower side of the contact glass;

a light leading member, positioned in front in a light outputtingdirection of the light output from the point light sources, configuredto lead the light output from the point light sources so as to irradiatealong a main scanning direction toward the document situated on thecontact glass; and

a photoelectric conversion element configured to receive reflectionlight from the document;

wherein the light leading member includes positioning-means configuredto make a gap between each of the point light sources arranged in a linestate and the light leading member constant and make an arrangementdirection of the point light sources be positioned along a longitudinaldirection of the light leading member.

According to the above-mentioned image reading apparatus, the lightsbeams from the point light sources are uniformly incident on the lightleading member. It is possible to uniformly light the document along amain scanning direction of the document by the light that is led by thelight leading member after being output from the point light source.

The image reading apparatus may further include:

a point light source array substrate where the point light sources areprovided in the line state;

wherein the positioning means is formed by a holding part and a contactstandard surface;

the holding part is provided in the light leading member;

the holding part has a mounting surface extending in parallel with thelongitudinal direction of the light leading member, the mounting surfacebeing where the point light source array substrate is mounted; and

the contact standard surface is formed in the light leading member andhas a structure where a contact surface formed in the substrate contactsthe contact standard surface by mounting the point light source arraysubstrate on the mounting surface.

According to the above-mentioned image reading apparatus, by mountingthe point light source array substrate on the mounting surface of theholding part, it is possible to makes an arrangement direction of theplural point light sources consistent with the longitudinal direction ofthe light leading member. In addition, by contacting the contact surfaceformed in the substrate with the contact standard surface of the lightleading member, it is possible to make a gap between each of the pointlight sources and the light leading member 31 constant. Thus, the lightbeams from the point light sources are uniformly incident on the lightleading member. It is possible to uniformly light the document along amain scanning direction of the document by the light that is led by thelight leading member after being output from the point light source.

The image reading apparatus may further include:

a point light source array substrate where the point light sources areprovided in the line state;

wherein the positioning means is formed by an insertion concave part anda contact standard surface;

the insertion concave part is provided in the light leading member andextends in parallel with the longitudinal direction of the light leadingmember; and

a contact surface formed in the substrate contacts the contact standardsurface formed deep in the insertion concave part by inserting thesubstrate in the insertion concave part.

According to the above-mentioned invention, by inserting the substratein the insertion concave part, it is possible to makes an arrangementdirection of the plural point light sources consistent with thelongitudinal direction of the light leading member. In addition, bycontacting the contact surface formed in the substrate with the contactstandard surface formed deep in the insertion concave part, it ispossible to make a gap between each of the point light sources and thelight leading member 31 constant. Thus, the light beams from the pointlight sources are uniformly incident on the light leading member. It ispossible to uniformly light the document along a main scanning directionof the document by the light that is led by the light leading memberafter being output from the point light sources. Furthermore, a bend ofthe substrate can be corrected by inserting the substrate in theinsertion concave part. Therefore, a gap between the point light sourceand the light leading member generated due to the bend of the substratecan be prevented. Therefore, lighting for the document can be furtheruniformly done along the main scanning direction of the document.

The image reading apparatus may further include:

a point light source array substrate where the point light sources areprovided in the line state;

wherein the positioning means is formed by an insertion concave part andan incident surface of the light leading member;

the insertion concave part is provided in the light leading member andextends in parallel with the longitudinal direction of the light leadingmember; and

an emitting surface of each of the point light source contacts theincident surface by inserting the substrate in the insertion concavepart.

According to the above-mentioned invention, by inserting the substratein the insertion concave part, it is possible to makes an arrangementdirection of the plural point light sources consistent with thelongitudinal direction of the light leading member. In addition, bycontacting the emitting surface of the point light sources with theincident surface of the light leading member, it is possible to make agap between each of the point light sources and the light leading member31 be constant. Thus, the light beams from the point light sources areuniformly incident on the light leading member. It is possible touniformly light the document along a main scanning direction of thedocument by the light that is led by the light leading member afterbeing output from the point light sources. Furthermore, a bend of thesubstrate can be corrected by inserting the substrate in the insertionconcave part. Therefore, a gap between the point light sources and thelight leading member generated due to the bend of the substrate can beprevented. Therefore, lighting for the document can be further uniformlydone along the main scanning direction of the document.

The image reading apparatus may further include:

a point light source array substrate where the point light sources areprovided in the line state;

wherein the positioning means is formed by a holding part and aplurality of installation screw holes;

the holding part is provided in the light leading member;

the holding part has a mounting surface extending in parallel with thelongitudinal direction of the light leading member, the mounting surfacebeing where the point light source array substrate is mounted; and

the installation screw holes are formed in the holding part, face aplurality of positioning holes formed in the substrate, and have astructure where fixing screws inserted in the positioning holes arescrew-fixed with the installation screw holes, by mounting the pointlight source array substrate on the mounting surface.

According to the above-mentioned invention, by mounting the point lightsource array substrate on the mounting surface of the holding part, itis possible to make an arrangement direction of the plural point lightsources consistent with the longitudinal direction of the light leadingmember. In addition, by facing the installation screw hole formed in theholding part toward the positioning hole formed in the substrate andfixing the fixing screw inserted in the positioning hole with theinstallation screw hole, it is possible to make a gap between each ofthe point light sources and the light leading member 31 constant. Thus,the light beams from the point light sources are uniformly incident onthe light leading member. It is possible to uniformly light the documentalong a main scanning direction of the document by the light that is ledby the light leading member after being output from the point lightsource.

One of a plurality of positioning holes, situated in the center part inthe longitudinal direction in the substrate, may have a circular holeshaped configuration having a substantially same outside diameter as thefixing screw;

a length along the longitudinal direction in the substrate of the otherpositioning hole may be longer than a diameter of the fixing screw; and

the length along a direction perpendicular to the longitudinal directionin the substrate of the other positioning hole may be the substantiallysame as the diameter of the fixing screw.

According to the above-mentioned invention, even if a thermal expansiondifference is generated between the holding part and the substratedepending on the change of the temperature, generation of a bend of theholding part or the substrate due to this thermal expansion differencecan be prevented. Hence, a position gap between the point light sourcesand the light leading member based on the bend due to the thermalexpansion difference can be prevented. Because of this, lighting for thedocument can be further uniformly done along the main scanning directionof the document.

The positioning means may be formed by a holding part and a wiringpattern;

the holding part may be provided in the light leading member;

the holding part may have a mounting surface extending in parallel withthe longitudinal direction of the light leading member; and

the wiring pattern may be formed on the mounting surface and isconnected to the point light source.

According to the above-mentioned invention, by forming the wiringpattern on the mounting surface provided in the light leading member andextending the wiring pattern in parallel with a longitudinal directionof the light leading member and by connecting the point light sources tothe wiring pattern, it is possible to makes an arrangement direction ofthe plural point light sources consistent with the longitudinaldirection of the light leading member and to make a gap between each ofthe point light sources and the light leading member 31 constant. Thus,the light beams from the point light sources are uniformly incident onthe light leading member. It is possible to uniformly light the documentalong a main scanning direction of the document by the light that is ledby the light leading member after being output from the point lightsource.

The image reading apparatus may further include:

a holding member having a plurality of press-fitting concave parts forthe point light sources;

wherein the point light sources are press-fitted in the press-fittingconcave parts;

the positioning means is formed by a holding part and a contact standardsurface;

the holding part is provided in the light leading member and has amounting surface extending in parallel with a longitudinal direction ofthe light leading member;

a wiring pattern is formed on the mounting surface; and

a contact surface formed in the holding member contacts the contactstandard surface formed on the light leading member, by mounting theholding member wherein the point light source is light press fitted inthe press-fitting concave part for the point light source, on themounting surface so that the point light source is connected to thewiring pattern.

According to the above-mentioned invention, by mounting the holdingmember, wherein the point light source is light press fitted in thepress-fitting concave part for the point light source, on the mountingsurface so that the point light source is connected to the wiringpattern, it is possible to make an electrical connection to the pointlight source. Furthermore, it is possible to make an arrangementdirection of the plural point light sources consistent with thelongitudinal direction of the light leading member. In addition, bycontacting the contact surface of the holding member with the contactstandard surface of the light leading member, it is possible to make agap between each of the point light sources and the light leading memberconstant. Thus, the light beams from the point light sources areuniformly incident on the light leading member. It is possible touniformly light the document along a main scanning direction of thedocument by the light that is led by the light leading member afterbeing output from the point light source. The point light sources aresimply light-press fitted to the corresponding press-fitting concaveparts for the point light sources of the holding member. Hence, if acertain point light source does not work, only the point light sourcewhich does not work is exchanged. Hence, it is not necessary to exchangethe entirety of plural point light sources. It is also not necessary toexchange the entirety of plural point light sources including the lightleading member. Hence, the maintenance when a point light source doesnot work can be implemented at low cost.

A press-fitting concave part for a peripheral circuit element where theperipheral circuit element is light-press-fitted may be formed in theholding part; and

the peripheral circuit element which is light-press-fitted in thepress-fitting concave part for the peripheral circuit element may beconnected to the wiring pattern.

According to the above-mentioned invention, it is possible to make anelectrical connection between the point light source and the peripheralcircuit element and therefore it is possible to achieve the same effectas the effect achieved by the invention claimed in claim 8. Furthermore,since the peripheral circuit elements are simply light-press-fitted tothe corresponding press-fitting concave parts of the holding member, ifa certain peripheral circuit element does not work, only the peripheralcircuit element which does not work is exchanged. Since only the wiringpattern 61 is formed on the mounting surface of the holding part, it isnot necessary to solder-fix the peripheral circuit elements.

The holding member may be made of metal.

It is possible to improve transferability and radiation-ability of heatgenerated by the point light source and the peripheral circuit elements,so that it is possible to prevent the performance of the point lightsource and the peripheral circuit elements from degrading due to theinfluence of the heat.

The holding member may have a heat radiation part.

It is possible to improve radiation-ability of heat generated by thepoint light source and the peripheral circuit element, so that it ispossible to prevent the performance of the point light source and theperipheral circuit element from degrading due to the influence of heat.

The image reading apparatus may further include:

a holding member having a plurality of press-fitting concave parts forthe point light sources, the press-fitting concave parts being partsinto which the point light sources are press-fitted; and

a substrate where a wiring pattern is formed;

wherein the positioning means is formed by a holding part and apositioning pin;

the holding part is provided in the light leading member and has amounting surface extending in parallel with the longitudinal directionof the light leading member in a state where the substrate and theholding member are stacked;

the positioning pin is fixed to the-holding part so as to pierce thesubstrate and the holding member for position fixing; and

the substrate is mounted on the mounting surface, in a state where thepoint light source light-press-fitted in the press-fitting concave partis connected to the wiring pattern.

According to the above-mentioned invention, by mounting the holdingmember, wherein the point light sources are press-fitted in thepress-fitting concave parts, and the substrate on the mounting surfaceof the holding part, it is possible to makes an arrangement direction ofthe plural point light sources consistent with the longitudinaldirection of the light leading member. In addition, by position fixingthe holding member mounted on the mounting surface and the substrate bythe positioning pin fixed to the holding part, it is possible to make agap between each of the point light sources and the light leading member31 constant. Thus, the light beams from the point light sources areuniformly incident on the light leading member. It is possible touniformly light the document along a main scanning direction of thedocument by the light that is led by the light leading member afterbeing output from the point light sources. Furthermore, since the wiringpattern is formed on an exclusive substrate, a special process forforming the wiring pattern on the mounting surface of the holding partis not necessary so that productivity can be improved.

The positioning pin may be formed in a body with the holding part.

According to the above-mentioned invention, it is possible to improvepositioning precision between the holding member and the holding part bythe positioning pin. Because of this, it is possible to uniformly lightthe document along a main scanning direction of the document.

The above-mentioned object of the present invention is achieved by animage forming apparatus, including:

an image reading apparatus; and

a printer engine configured to form an image on a recording mediumcorresponding to image data read by the image reading apparatus;

wherein the image reading apparatus includes

a plurality of point light sources, arranged in a straight line state,configured to output light for lighting a document situated on a contactglass from a lower side of the contact glass;

a light leading member, positioned in front in a light outputtingdirection of the light output from the point light source, configured tolead the light output from the point light source so as to irradiatealong a main scanning direction toward the document situated on thecontact glass; and

a photoelectric conversion element configured to receive reflectionlight from the document;

wherein the light leading member includes positioning means configuredto cause a gap between each of the point light sources arranged in aline state and the light leading member to be made constant and make anarrangement direction of the point light sources be positioned along thelongitudinal direction of the light leading member.

According to the above-mentioned invention, it is possible to form theimage corresponding to the stable image reading result by the imagereading apparatus. Therefore, it is possible to improve the formed imagequality.

Other objects, features, and advantages of the present invention willbecome more apparent from the following detailed description when readin conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal sectional view of a related art lightingdevice;

FIG. 2 is a perspective view showing a case where a light leading memberand an LED array substrate are shifted in a direction where a distancebetween LEDs and the light leading member is not constant;

FIG. 3 is a perspective view showing a case where the light leadingmember and the LED array substrate are shifted in a direction where anarrangement direction of the LEDs and a longitudinal direction of thelight leading member are twisted;

FIG. 4 is a schematic front view of an internal structure of afull-color copying machine 1 of a first embodiment of the presentinvention;

FIG. 5 is a perspective view of a structure of a lighting device;

FIG. 6 is a longitudinal sectional view of the lighting device;

FIG. 7 is a perspective view showing a structure of a lighting device ofa second embodiment of the present invention;

FIG. 8 is a longitudinal sectional view of the lighting device shown inFIG. 7;

FIG. 9 is a perspective view showing a structure of a lighting device ofa third embodiment of the present invention;

FIG. 10 is a longitudinal sectional view of the lighting device shown inFIG. 9;

FIG. 11 is a perspective view showing a structure of a lighting deviceof a fourth embodiment of the present invention;

FIG. 12 is a longitudinal sectional view of a part of positioning means;

FIG. 13 is a longitudinal sectional view of another part of thepositioning means;

FIG. 14 is a perspective view showing a structure of a lighting deviceof a fifth embodiment of the present invention;

FIG. 15 is a longitudinal sectional view of the lighting device shown inFIG. 14;

FIG. 16 is an exploded perspective view showing a structure of alighting device of a sixth embodiment of the present invention;

FIG. 17 is a longitudinal sectional view of the lighting device shown inFIG. 16;

FIG. 18 is an exploded perspective view showing a structure of alighting device of a seventh embodiment of the present invention;

FIG. 19 is a longitudinal sectional view of the lighting device shown inFIG. 18;

FIG. 20 is a longitudinal sectional view of a structure of a lightingdevice of an eighth embodiment of the present invention;

FIG. 21 is a longitudinal sectional view of a structure of a lightingdevice of a ninth embodiment of the present invention; and

FIG. 22 is a longitudinal sectional view of a structure of a lightingdevice of a tenth embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A description of the present invention and details of drawbacks of therelated art are now given, with reference to FIG. 4 through FIG. 22,including embodiments of the present invention.

A first embodiment of the present invention is discussed with referenceto FIG. 4 through FIG. 6. FIG. 4 is a schematic front view of aninternal structure of a full-color copying machine 1 of a firstembodiment of the present invention. FIG. 5 is a perspective view of astructure of a lighting device. FIG. 6 is a longitudinal sectional viewof the lighting device 18.

A printer engine 3 for forming a color image is provided in a centralpart in an apparatus body 2 of the copying machine 1. This printerengine 3 includes: four drum-like photosensitive members 4 that arearranged in parallel horizontally to be spaced apart at an equalinterval; charging rollers 5 that form toner images on outer peripheralsurfaces of the photosensitive members 4; an exposing device 6 thatexposes the uniformly charged outer peripheral surfaces of thephotosensitive members 4 to a laser beam according to image data tothereby form electrostatic latent images on the outer peripheralsurfaces; developing devices 7 that supply toner to the electrostaticlatent images so as to change the electrostatic latent images to tonerimages; an intermediate transfer belt 8 on which toner images formed onthe outer peripheral surfaces of the respective photosensitive members 4are sequentially transferred; cleaning devices 9 that removes the tonerremaining on the photosensitive members 4 after the toner images aretransferred onto the intermediate transfer belt 8; a transfer roller 10that transfers the toner image on the intermediate transfer belt 8 ontoa recording medium S, and others. Toner images of Y (yellow), M(magenta), C (cyan), and B (black) are formed in the four photosensitivemembers 4, respectively. The toner images of these colors arerespectively transferred onto the intermediate transfer belt 8 in turnso that a color toner images is formed on the intermediate transfer belt8 and the color toner image is transferred to the recording medium S.

An ADF (automatic document feeder) 11, which automatically feeds adocument D that is the object to be lighted by the lighting device 18, acontact glass 12 where the document D is provided, and an image readingapparatus 13 which reads the document automatically fed by the ADF 11 orthe document placed on the contact glass 12, are arranged above theapparatus body 12.

The image reading apparatus 13 includes: first and second travelingbodies 14 and 15 that are capable of traveling at speeds in the ratio of2:1 in parallel with the contact glass 12; a lens 16; and a CCD 17serving as a photoelectric conversion element. The first traveling body14 is equipped with a lighting device 18 for lighting a surface of thedocument D placed on the contact glass 12 or the document conveyed bythe ADF 11 and a first mirror 19 that reflects light reflected on thesurface of the document D and traveling along a reading optical axis.The second traveling body 15 is mounted with a second mirror 20 and athird mirror 21 that further reflect the light reflected by the firstmirror 19. The lens 16 and the CCD 17 are arranged in a travelingdirection of the reading light sequentially reflected by the firstthrough third mirrors 19, 20, and 21. The CCD 17 receives a reflectionlight (reading light) reflected by the document D after the light isoutput from the lighting device 18 to the document D.

Sheet cassettes 22 of plural stages, for example, four stages, in whichrecording media S are stored, are provided below the apparatus body 2.The recording media S stored in these sheet cassettes 22 are separatedand fed one by one by pickup rollers 23 and feed rollers 24. Theseparated and fed sheets are conveyed along a sheet conveying path 25provided in the apparatus body 2. A registration roller 26, the transferroller 10, a fixing device 27, a discharge roller 28, and the like arearranged along this sheet conveying path 25.

Depending on the conveyance timing and timing for image-forming on theintermediate transfer belt 8, the registration roller 26 isintermittently rotated. By stopping the rotation of the registrationroller 26, the recording medium conveyed to the sheet conveying path 25is stopped for a while and the recording medium S is sent out byrotating the registration roller 26. The recording medium S sent out bythe rotation of the registration roller 26 is conveyed to a transferringposition that is put between the intermediate transfer belt 8 and thetransfer roller 10.

The fixing device 27 applies heat and pressure to the recording medium Swhere the toner image is transferred so that the toner is melted. As aresult of this, the toner image is fixed to the recording medium S.

Under this structure, an action for forming an image in the copyingmachine 1 is done as follows. First, forming of the toner image isstarted at the printer engine 3. At the time when the toner image isformed, first of all, the image of the document D placed on the contactglass 12 or automatically conveyed by the ADF 11 is read out by theimage reading apparatus 13. In such a structure, laser beamscorresponding to image data of respective colors (yellow Y, magenta M,cyan C, and black B) are emitted from semiconductor lasers of theexposing device 6 according to a result of reading by the image readingapparatus 13. The laser beams expose the outer peripheral surfaces ofthe respective photosensitive members 4 that are uniformly charged bythe charging rollers 5, whereby electrostatic latent images are formed.Toners of the respective colors are supplied to the electrostatic latentimages from the respective developing devices 7, whereby toner images ofthe respective colors are formed. The toner images on the respectivephotosensitive members 4 are sequentially transferred onto theintermediate transfer belt 8, which moves in synchronization with thephotosensitive members 4, and a color toner image is formed on theintermediate transfer belt 8.

On the other hand, the recording medium S is started to be separated andfed from the inside of the sheet cassettes 22 before or after the startof the image forming operation in the printer engine. The recordingmedium S separated, fed, and conveyed through the sheet conveying path25 is timed by the registration roller 26 that is driven to rotateintermittently so as to be sent to a transferring position between theintermediate transfer belt 8 and the transferring roller 10.

When the recording medium S is sent to the transferring position betweenthe intermediate transfer belt 8 and the transfer roller 10, the colortoner image on the intermediate transfer belt 8 is transferred onto therecording medium S. The recording medium S where the color toner imageis transferred is conveyed on the sheet conveyance path 25 so that thecolor toner image is fixed on the recording medium S in a course ofpassing through the fixing device 27. The recording medium S having thecolor toner image fixed thereon is discharged onto a discharge tray 29by the discharge roller 28.

Under this structure, the lighting device of this embodiment, as shownin FIG. 5 and FIG. 6, includes an LED array substrate 30 that is a pointlight source array substrate and a light leading member 31. The LEDarray substrate 30 includes a substrate 33 and plural LEDs 32 as lightsources. The LEDs 32 are arranged and fixed in a straight line state ata designated equal pitch on the substrate 33 having a linerconfiguration. The LEDs 32 are arranged in a longitudinal direction ofthe substrate 33. This arrangement direction is consistent with a mainscanning direction of the document D at the time when an image is readin a case where the lighting device 18 is installed in the image readingapparatus 13. In addition, a wiring pattern (not shown) where the fixedLEDs 32 are electrically connected is formed in the substrate 33.Furthermore, in this LED array substrate 30, a periphery circuit element(not shown) including an electric current limiting register is connectedand fixed to the wiring pattern. Although a case where one line of theLEDs 32 is provided in the straight line state is discussed in thisembodiment as an example, LEDs of plural lines along the directionconsistent with the main scanning direction of the document D may beprovided at the time when the image is read.

The light leading member 31 is made of transparent resin such as acrylicor polycarbonate, glass, or the like. The light leading member 31 ispositioned in front of the outputting direction of the light output fromthe LEDs 32 to the document D. The light leading member 31 includes anincident surface 31 a and outputting surface 31 b. The light output fromthe LEDs 32 is incident on the incident surface 31 a. The incident lightis output toward the document D along the main scanning direction of thedocument D via the outputting surface 31 b. The light leading member 31has a linear configuration and extends along the arrangement directionof the LEDs 32.

A holding part 34 is formed in a body at a side of the incident surface31 a of the light leading member 31. The holding part 34 holds the LEDarray substrate 30 and extends along a longitudinal direction of thelight leading member 31. In the holding part 34, a mounting surface isformed so as to be parallel to a longitudinal direction of the lightleading member 31 and orthogonal to the incident surface 31 a. The LEDarray substrate 30 is attached to the holding part 34 in a direction inwhich a bottom surface of the substrate 33 is mounted on the mountingsurface 34 a. The bottom surface of the substrate 33 and the mountingsurface 34 a are adhered by an adhesive or stuck by double-sided tape toeach other, so that the LED array substrate 30 is fixed to the holdingpart 34.

An area which is a part of the incident surface 31 a of the lightleading member 31 and is adjacent to the mounting surface 34 a works asa contact standard surface 35. A surface which is along a longitudinaldirection of the substrate 33 and faces the contact standard surface 35when the LED array substrate 30 is mounted on the mounting surface 34 ais a contact surface 36, which contacts the contact standard surface 35.A positioning member 37 is formed in the light leading member 31. Thepositioning member 37 makes a gap between each of the LEDs 32 arrangedin a line state and the light leading member 31 constant by the holdingpart 34 having the mounting surface 34 a and the contact standardsurface 35. The positioning member 37 also makes an arrangementdirection of the LEDs 32 to be positioned along the longitudinaldirection of the light leading member 31.

Under this structure, as shown in FIG. 5 and FIG. 6, the LED arraysubstrate 30 is mounted on the mounting surface 34 a of the holding part34 and fixed to the holding part 34 by the adhesive or the double-sidedtape. The bottom surface of the substrate 33 is mounted on the mountingsurface 34 a and the contact surface 36 of the substrate 33 contacts thecontact standard surface 35 of the light leading member 31.

The mounting surface 34 a is a surface extending in parallel with thelongitudinal direction of the light leading member 31. Thus, by mountingthe LED array substrate 30 on the mounting surface 34 a, it is possibleto position plural LEDs 32 and the light leading member 31 so that thearrangement direction of the LEDs 32 is consistent with the longitudinaldirection of the light leading member 31. In addition, by contacting thecontact surface of the substrate 33 with the contact standard surface 35of the light leading member 31, it is possible for the gap between eachof the LEDs 32 and the incident surface 31 a of the light leading member31 to be made constant. Because of this, the light beams from the LEDs32 are incident on the incident surface 31 a of the light leading member31. It is possible to uniformly light the document D along a mainscanning direction of the document D by the light that is led by thelight leading member 31 after being output from the LEDs 32 and thenoutput from the outputting surface 31 b. Because of this, a lightreceiving property of a light received by a CCD 17 is improved andtherefore it is possible to improve the quality of an image formed bythe printer engine 3 based on a result of reading by the image readingapparatus 13.

In this embodiment, it is preferable that a fixing position of the LEDarray substrate 30 be positioned so that the LEDs 32 face the incidentsurface 31 a at a substantially center position of a width “A” in adirection perpendicular to the longitudinal direction of the outputtingsurface 31 b of the light leading member 31, namely a sub-scanningdirection at the time of image reading.

Although the holding part 34 is uniformly formed with the light leadingmember 31 in this embodiment, the present invention is not limited tothis. For example, the holding part 34 may be formed separately from thelight leading member 31 and this holding part 34 may be fixed to thelight leading member 31.

Next, the second embodiment of the present invention is discussed withreference to FIG. 7 and FIG. 8. In FIG. 7 and FIG. 8, parts that are thesame as the parts discussed above are given the same reference numerals,and explanation thereof is omitted. FIG. 7 is a perspective view showinga structure of the lighting device of the second embodiment of thepresent invention. FIG. 8 is a longitudinal sectional view of thelighting device shown in FIG. 7.

In this embodiment, a lighting device 40 is provided for lighting thedocument D situated on the contact glass 12 from a lower side of thecontact glass 12. The image reading apparatus 13 (See FIG. 4) is formedby the lighting device 40 and the CCD 17 (See FIG. 4) reading areflection light (reading light) reflected by the document D after thelight output from the lighting device 40 is irradiated on the documentD.

The lighting device 40 includes the LED array substrate 30 and the lightleading member 31. The LED array substrate 30 includes plural LEDs 32.The LEDs 32 are arranged and fixed in a straight line state at adesignated equal pitch on the substrate 33 having a liner configuration.The LEDs 32 are arranged in a longitudinal direction of the substrate33. This arrangement direction is consistent with a main scanningdirection of the document D at the time when an image is read in a casewhere the lighting device 40 is installed in the image reading apparatus13.

The light leading member 31 is made of transparent resin such as acrylicor polycarbonate, glass, or the like. The light leading member 31 ispositioned in front of the outputting direction of the light output fromthe LEDs 32 to the document D. The light leading member 31 includes anincident surface 31 a and outputting surface 31 b. The light output fromthe LEDs 32 is incident on the incident surface 31 a. The incident lightis output toward the document D along the main scanning direction of thedocument D via the outputting surface 31 b. The light leading member 31has a linear configuration and extends along the arrangement directionof the LEDs 32.

The holding part 34 is formed in a body at the side of the incidentsurface 31 a of the light leading member 31. The holding part 34 holdsthe LED array substrate 30 and extends along the longitudinal directionof the light leading member 31. In the holding part 34, the mountingsurface is formed so as to be in parallel with the longitudinaldirection of the light leading member 31 and orthogonal to the incidentsurface 31 a. The LED array substrate 30 is attached to the holding part34 in the direction in which a bottom surface of the substrate 33 ismounted on the mounting surface 34 a. See FIG. 5.

A bottom surface forming a single surface with the mounting surface 34 ais formed at a side of the incident surface 31 a of the light leadingmember 31. An insertion concave part is formed at the side of theincident surface 31 a of the light leading member 31 so as to extend inparallel with the longitudinal direction of the light leading member 31.A height “B” of the insertion concave part 41 is slightly greater thanthe thickness of the substrate 33. One side along the longitudinaldirection of the substrate 33 is inserted into the insertion concavepart 41 so that the LED array substrate 30 is fixed to the light leadingmember 31.

A surface deep in the insertion concave part 41 works as a contactstandard surface 42 and extends in parallel with the longitudinaldirection of the light leading member 31. A surface which is along alongitudinal direction in the substrate 33 and which is inserted in theinsertion concave part 41 is a contact surface 43, which is made tocontact the contact standard surface 42 by inserting the substrate 33 inthe insertion concave part 41. A positioning member 44 makes a gapbetween each of the LEDs 32 arranged in a line state and the lightleading member 31 constant by contact between the insertion concave part41 and the contact standard surface 42. The positioning member 44 alsocauses an arrangement direction of the LEDs 32 position to be along thelongitudinal direction of the light leading member 31.

Under this structure, as shown in FIG. 7 and FIG. 8, the LED arraysubstrate 30 is fixed to the light leading part 31 by inserting thesubstrate 33 in the insertion concave part 41 so that the contactsurface 43 of the substrate 33 contacts the contact standard surface 42formed deep in the insertion concave part 41. The bottom surface of thesubstrate 33 contacts the mounting surface 34 a of the holding part 34.

The insertion concave part 41 extends in parallel with the longitudinaldirection of the light leading member 31. Hence, by inserting thesubstrate 33 of the LED array substrate 30 in the insertion concave part41, it is possible to position plural LEDs 32 and the light leadingmember 31 so that the arrangement direction of the LEDs 32 is consistentwith the longitudinal direction of the light leading member 31. Inaddition, by contacting the contact surface 43 of the substrate 33 withthe contact standard surface 42 formed deep in the insertion concavepart 41, it is possible for the gap between each of the LEDs 32 and theincident surface 31 a of the light leading member 31 to be madeconstant. Because of this, the light beams from the LEDs 32 areuniformly incident on the incident surface 31 a of the light leadingmember 31. It is possible to uniformly light the document D along a mainscanning direction of the document D by the light that is led by thelight leading member 31 after being output from the LED 32 and thenoutput from the outputting surface 31 b. Because of this, a lightreceiving property of a light received by a CCD 17 is improved andtherefore it is possible to improve the quality of an image formed bythe printer engine 3 based on a result of reading by the image readingapparatus 13.

Furthermore, according to this embodiment, a bend of the substrate 33can be corrected by inserting the substrate 33 in the insertion concavepart 41. Therefore, a gap between the LEDs 32 and the light leadingmember 31 generated due to the bend of the substrate 33 can beprevented. Therefore, lighting for the document D can be furtheruniformly done along the main scanning direction of the document D.

Next, the third embodiment of the present invention is discussed withreference to FIG. 9 and FIG. 10. FIG. 9 is a perspective view showing astructure of the lighting device of the third embodiment of the presentinvention. FIG. 10 is a longitudinal sectional view of the lightingdevice shown in FIG. 9.

In this embodiment, a lighting device 50 is provided for lighting thedocument D situated on the contact glass 12 from a lower side of thecontact glass 12. The image reading apparatus 13 (See FIG. 4) is formedby the lighting device 50 and the CCD 17 (See FIG. 4) reading areflection light (reading light) reflected by the document D after thelight output from the lighting device 50 is irradiated on the documentD.

The lighting device 50 includes the LED array substrate 30 and the lightleading member 31. The LED array substrate 30 includes plural LEDs 32.The LEDs 32 are arranged and fixed in a straight line state at adesignated equal pitch on the substrate 33 having a linearconfiguration. The LEDs 32 are arranged in a longitudinal direction ofthe substrate 33. This arrangement direction is consistent with a mainscanning direction of the document D at the time when image is read in acase where the lighting device 50 is installed in the image readingapparatus 13.

The light leading member 31 includes an incident surface 31 a andoutputting surface 31 b. The light leading member 31 has a linearconfiguration and extends along the arrangement direction of the LEDs32. The holding part 34 and the insertion concave part 41 are formed inthe light leading member 31. A height “B” of the insertion concave part41 is slightly greater than the thickness of the substrate 33. One sidealong the longitudinal direction of the substrate 33 is inserted in theinsertion concave part 41 so that the LED array substrate 30 is fixed tothe light leading member 31.

By inserting the substrate 33 in the insertion concave part 41 so thatthe LED array substrate 30 is fixed to the light leading member 31, anemission surface 32 a of the LED 32 contacts the incident surface 31 aof the light leading member 31 positioned at an entrance side edge partof the insertion concave part 41. A positioning member 51 makes a gapbetween each of the LEDs 32 arranged in a line state and the lightleading member 31 constant by the insertion concave part 41 and theincident surface 31 a positioned at the entrance side edge part of theinsertion concave part 41. The positioning member 44 also makes anarrangement direction of the LEDs 32 to be positioned along thelongitudinal direction of the light leading member 31.

Under this structure, as shown in FIG. 9 and FIG. 10, the LED arraysubstrate 30 is fixed to the light leading part 31 by inserting thesubstrate 33 in the insertion concave part 41 so that the emissionsurface 32 a of the LED 32 contacts the incident surface 31 a of thelight leading member 31 positioned at the entrance side edge part of theinsertion concave part 41. The bottom surface of the substrate 33contacts the mounting surface 34 a of the holding part 34.

The insertion concave part 41 extends in parallel with the longitudinaldirection of the light leading member 31. Hence, by inserting thesubstrate 33 of the LED array substrate 30 in the insertion concave part41, it is possible to position plural LEDs 32 and the light leadingmember 31 so that the arrangement direction of the LEDs 32 is consistentwith the longitudinal direction of the light leading member 31. Inaddition, by contacting the emission surface 32 a of the LED 32 with theincident surface 31 a of the light leading member 31, it is possible tomake the gap between each of the emission surface 32 a of the LEDs 32and the incident surface 31 a of the light leading member 31 constant (alength of the gap is “0”). Because of this, the light beams from theLEDs 32 are uniformly incident on the light leading member 31. It ispossible to uniformly light the document D along a main scanningdirection of the document D by the light that is led by the lightleading member 31 after being output from the LED 32 and then outputfrom the outputting surface 31 b. Because of this, a light receivingproperty of a light received by a CCD 17 is improved and therefore it ispossible to improve the quality of an image formed by the printer engine3 based on a result of reading by the image reading apparatus 13.

Furthermore, according to this embodiment, a bend of the substrate 33can be corrected by inserting the substrate 33 in the insertion concavepart 41. Therefore, a gap between the LEDs 32 and the light leadingmember 31 generated due to the bend of the substrate 33 can beprevented. Therefore, lighting for the document D can be furtheruniformly done along the main scanning direction of the document D.

Next, the fourth embodiment of the present invention is discussed withreference to FIG. 11 through FIG. 13. FIG. 11 is a perspective viewshowing a structure of the lighting device of the fourth embodiment ofthe present invention. FIG. 12 is a longitudinal sectional view of apart of positioning means. FIG. 13 is a longitudinal sectional view ofanother part of the positioning means.

In this embodiment, a lighting device 55 is provided for lighting thedocument D situated on the contact glass 12 from a lower side of thecontact glass 12. The image reading apparatus 13 (See FIG. 4) is formedby the lighting device 55 and the CCD 17 (See FIG. 4) reading areflection light (reading light) reflected by the document D after thelight output from the lighting device 55 is irradiated on the documentD.

The lighting device 55 includes the LED array substrate 30 and the lightleading member 31. The LED array substrate 30 includes plural LEDs 32.The LEDs 32 are arranged and fixed in a straight line state at adesignated equal pitch at the substrate 33 having a linearconfiguration. The LEDs 32 are arranged in a longitudinal direction ofthe substrate 33. This arrangement direction is consistent with a mainscanning direction of the document D at the time when an image is readin a case where the lighting device 55 is installed in the image readingapparatus 13.

A holding part 34 is formed in a body at a side of the incident surface31 a of the light leading member 31. The holding part 34 holds the LEDarray substrate 30 and extends along a longitudinal direction of thelight leading member 31. In the holding part 34, a mounting surface 34 ais formed so as to be in parallel with a longitudinal direction of thelight leading member 31 and orthogonal to the incident surface 31 a. TheLED array substrate 30 is attached to the holding part 34 in a directionso that a bottom surface of the substrate 33 is mounted on the mountingsurface 34 a.

Plural installation screw holes 56 are formed in the holding part 34along the longitudinal direction of the light leading member 31. Pluralpositioning holes 57 (57 a and 57 b) are formed in the substrate 33 soas to face the installation screw holes 56 by holding the LED arraysubstrate 30 to contact the holding part 34. The LED array substrate 30is mounted on the mounting surface 34 a. Positions of the positioningholes 57 and the installation screw holes 56 are adjusted in upper andlower directions. Then, fixing screws 58 inserted in the positioningholes 57 is screw-fixed to the corresponding installation screw holes 56so that the LED array substrate 30 is fixed to the holding part 34.

A positioning member 51 causes a gap between each of the LEDs 32arranged in a line state and the light leading member 31 to be constantby the holding part 34 having the mounting surface 34 a and theinstallation screw holes 56 into which the fixing screws 58 are insertedand screw-fixed. The positioning member 51 also makes an arrangementdirection of the LEDs 32 to be positioned along the longitudinaldirection of the light leading member 31.

A single positioning hole 57 a, situated in the center part in thelongitudinal direction in the substrate 33, among plural positioningholes 57 (57 a and 57 b) has a circular hole shaped configuration havinga substantially same outside diameter as the fixing screw 58. The lengthalong the longitudinal direction in the substrate 33 of otherpositioning holes 57 b is longer (elongated) than the diameter of thefixing screw 58. The length along a direction perpendicular to thelongitudinal direction in the substrate 33 of other positioning holes 57b is the substantially the same as the diameter of the fixing screw 58.

Under this structure, as shown in FIG. 11, the LED array substrate 30 ismounted on the mounting surface 34 a of the holding part 34. Positionsof the positioning holes 57 and the corresponding installation screwholes 56 face each other. Then, the fixing screws 58 inserted in thepositioning holes 57 are screw-fixed to the installation screw holes 56so that the LED array substrate 30 is fixed to the holding part 34.

The mounting surface 34 a extends in parallel with the longitudinaldirection of the light leading member 31. Hence, by mounting the LEDarray substrate 30 on the mounting surface 34 a, it is possible toposition plural LEDs 32 and the light leading member 31 so that thearrangement direction of the LEDs 32 is consistent with the longitudinaldirection of the light leading member 31. In addition, by facing theinstallation screw holes 56 formed in the holding part 34 to thepositioning holes 57 formed in the substrate 33 and screw-fixing thefixing screws 58, inserted in the positioning holes 57, into thecorresponding installation screw holes 56, it is possible to cause thegap between each of the emission surface of the LEDs 32 and the incidentsurface 31 a of the light leading member 31 to be made constant. Becauseof this, the light beams from the LEDs 32 are uniformly incident on thelight leading member 31. It is possible to uniformly light the documentD along a main scanning direction of the document D by the light that isled by the light leading member 31 after being output from the LEDs 32and then output from the outputting surface 31 b. Because of this, alight receiving property of light received by a CCD 17 is improved andtherefore it is possible to improve the quality of an image formed bythe printer engine 3 based on a result of reading by the image readingapparatus 13.

In this embodiment, a single positioning hole 57 a, situated in thecenter part in the longitudinal direction in the substrate 33 has acircular hole shaped configuration having a substantially same outsidediameter as the fixing screw 58. The length along the longitudinaldirection in the substrate 33 of other positioning hole 57 b is longerthan the diameter of the fixing screw 58. The length along a directionperpendicular to the longitudinal direction in the substrate 33 of theother positioning hole 57 b is substantially the same as the diameter ofthe fixing screw 58. Therefore, even if a thermal expansion difference(a thermal expansion difference in the direction along the longitudinaldirection of the substrate 33 and the holding part 34) is generatedbetween the holding part 34 and the substrate 33 due to a change oftemperature, this thermal expansion difference can be accommodated by agap between the internal circumferential surface of each of thepositioning holes 57 b and an external circumferential surface of thecorresponding fixing screw 58, namely a gap existing along thelongitudinal direction of the substrate 33 and the holding part 34.Hence, the generation of a bend of the holding part 34 or the substrate33 due to the thermal expansion difference between the holding part 34and the substrate 33 can be prevented. Hence, a position gap between theLEDs 32 and the light leading member 31 based on a bend due to thermalexpansion difference can be prevented. Because of this, lighting for thedocument D can be further uniformly done along the main scanningdirection of the document D.

It is preferable to form a fine gap G (See FIG. 13) between a head partof the fixing screw 58 being inserted in the positioning screw hole 57 band an upper surface of the substrate 33. The fine gap G accommodates arelative movement of the fixing screw 58 and the substrate 33 when athermal expansion difference is generated.

Next, the fifth embodiment of the present invention is discussed withreference to FIG. 14 and FIG. 15. FIG. 14 is a perspective view showinga structure of the lighting device of the fifth embodiment of thepresent invention. FIG. 15 is a longitudinal sectional view of thestructure of the lighting device.

In this embodiment, a lighting device 60 is provided for lighting thedocument D situated on the contact glass 12 from a lower side of thecontact glass 12. The image reading apparatus 13 (See FIG. 4) is formedby the lighting device 60 and the CCD 17 (See FIG. 4) reading areflection light (reading light) reflected by the document D after thelight is output from the lighting device 60 is irradiated on thedocument D.

The lighting device 60 includes plural LEDs 32 and the light leadingmember 31. A holding part 34 is formed in a body at a side of theincident surface 31 a of the light leading member 31. The holding part34 extends along a longitudinal direction of the light leading member31. In the holding part 34, a mounting surface 34 a is formed so as tobe in parallel with a longitudinal direction of the light leading member31 and orthogonal to the incident surface 31 a.

A wiring pattern 61 is formed on the mounting surface 34 a of theholding part 34. Plural LEDs 32 and plural peripheral circuit elements62 such as an electric current limiting resistance are connected to thewiring pattern 61. The LEDs 32 and the peripheral circuit elements 62are positioned at designated positions on the wiring pattern 61 andsolder-fixed so as to be mounted on the holding part 34.

A positioning member 63 makes a gap between each of the LEDs 32 arrangedin a line state and the light leading member 31 constant by the holdingpart 34 having the mounting surface 34 a and the wiring pattern 61 whichis formed on the mounting surface 34 a and to which the LEDs 32 and theperipheral circuit elements 62 are connected. The positioning member 63also makes an arrangement direction of the LEDs 32 to be positionedalong the longitudinal direction of the light leading member 31.

Under this structure, in this embodiment, the wiring pattern 61 isformed in the holding part 34 which is formed uniformly with the lightleading member 31. The LEDs 32 and the peripheral circuit elements 62connected to the wiring pattern 61 are mounted on the holding part 34.

The wiring pattern 61 is formed on the mounting surface 34 a of theholding part 34 formed uniformly with the light leading member 31 andextending in parallel with the longitudinal direction of the lightleading member 31. By connecting the plural LEDs 32 to the wiringpattern 61, it is possible to position plural LEDs 32 and the lightleading member 31 so that the arrangement direction of the LEDs 32 isconsistent with the longitudinal direction of the light leading member31. In addition, it is possible to cause the gap between each of theemission surface of the LEDs 32 and the incident surface 31 a of thelight leading member 31 to be made constant. Because of this, the lightbeams from the LEDs 32 are uniformly incident on the light leadingmember 31. It is possible to uniformly light the document D along a mainscanning direction of the document D by the light that is led by thelight leading member 31 after being output from the LED 32 and thenoutput from the outputting surface 31 b. Because of this, a lightreceiving property of light received by a CCD 17 is improved andtherefore it is possible to improve the quality of an image formed bythe printer engine 3 based on a result of reading by the image readingapparatus 13.

Next, the sixth embodiment of the present invention is discussed withreference to FIG. 16 and FIG. 17. FIG. 16 is an exploded perspectiveview showing a structure of the lighting device of the sixth embodimentof the present invention. FIG. 17 is a longitudinal sectional view ofthe lighting device shown in FIG. 16.

In this embodiment, a lighting device 65 is provided for lighting thedocument D situated on the contact glass 12 from a lower side of thecontact glass 12. The image reading apparatus 13 (See FIG. 4) is formedby the lighting device 65 and the CCD 17 (See FIG. 4) reading areflection light (reading light) reflected by the document D after thelight output from the lighting device 65 is irradiated on the documentD.

The lighting device 65 includes plural LEDs 32, the light leading member31, and a holding member 66 holding the LEDs 32. A holding part 34 isformed in a body at a side of the incident surface 31 a of the lightleading member 31. The holding part 34 extends along a longitudinaldirection of the light leading member 31. In the holding part 34, amounting surface 34 a is formed so as to be in parallel with alongitudinal direction of the light leading member 31 and orthogonal tothe incident surface 31 a.

A wiring pattern 61 is formed on the mounting surface 34 a of theholding part 34. Plural peripheral circuit elements 62 such as anelectric current limiting resistance are connected to the wiring pattern61. The peripheral circuit elements 62 are positioned at designatedposition on the wiring pattern 61 and solder-fixed so as to be mountedon the holding part 34. Plural screw holes 67 are formed at positions inthe holding part 34 along the longitudinal direction of the holding part34.

Plural press-fitting concave parts 68 for the point light sources,plural screw insertion holes 69, and plural escaping holes 70 are formedin the holding member 66. The press-fitting concave parts 68 for thepoint light sources, screw insertion holes 69, and escaping holes 70 arearranged in a straight line state along the longitudinal direction ofthe holding member 66. The LEDs 32 are light-press-fitted into thepress-fitting concave parts 68 for the point light sources. Theperipheral circuit elements 62 fit in the escaping holes 70 by fixingthe holding member 66 to the holding part 34. The holding member 66light-press-fits the LEDs 32 into the press-fitting concave parts 68 forthe point light sources, which makes the LED 32 face the electricalconnection position over the wiring pattern 61, and makes the screwinsertion holes 69 face the corresponding screw holes 67, so as to bemounted on the mounting surface 34 a of the holding part 34. The holdingmember 66 is fixed to the holding part 34 by screw-fixing the fixingscrew 71 inserted in the screw insertion hole 69 with the screw holes67. The LEDs 32 are pressed and connected at the designated position onthe wiring pattern 61 by the above-discussed fixing. The arrangementdirection of the press-fitting concave parts 68 for the point lightsources is consistent with the main scanning direction of the document Dat the time when the image is read in a case where the lighting device65 is installed in the image reading apparatus 13.

An area which is a part of the incident surface 31 a of the lightleading member 31 and is adjacent to the mounting surface 34 a works asa contact standard surface 72. A surface which is along a longitudinaldirection in the holding member 66 and faces the contact standardsurface 35 by mounting the holding member 66 on the holding part 34 is acontact surface 73 which contacts the contact standard surface 72. Apositioning member 74 is formed in the light leading member 31. Thepositioning member 74 makes a gap between each of the LEDs 32 arrangedin a line state and the light leading member 31 constant by the holdingpart 34 having the mounting surface 34 a on which the wiring pattern 61is formed and the contact standard surface 72. The positioning member 37also makes an arrangement direction of the LEDs 32 be positioned alongthe longitudinal direction of the light leading member 31.

The holding member 66 is made of metal such as aluminum, copper, analuminum alloy, or a copper alloy. By using a die-casting method, anextrusion method, or a sintering method, for example, as a method forforming the holding member 66 made of metal, it is possible to easilyform the holding member 66 having a large number of small press-fittingconcave parts 68 for the point light sources and escaping holes 70.

Under this structure, the holding member 66 holding the LEDs 32 is fixedto the holding part 34 where the wiring pattern 61 is formed by usingthe fixing screws 71 so that the LEDs 32 are pressed and connected tothe wiring pattern 61 formed on the mounting surface 34 a of the holdingpart 34. Because of this, it is possible to electrically connect theLEDs 32.

The mounting surface 34 a extends in parallel with the longitudinaldirection of the light leading member 31. Hence, by mounting the holdingmember 66 light-press-fitting the LEDs 32 to the press-fitting concaveparts 68 for the point light sources on the mounting surface 34 a, it ispossible to position plural LEDs 32 and the light leading member 31 sothat the arrangement direction of the LEDs 32 is consistent with thelongitudinal direction of the light leading member 31. In addition, bycontacting the contact surface 73 of the holding member 66 with thecontact standard surface 72 of the light leading member 31, it ispossible to cause the gap between each of the LEDs 32 and the incidentsurface 31 a of the light leading member 31 to be made constant. Becauseof this, the light beams from the LEDs 32 are uniformly incident on theincident surface 31 a of the light leading member 31. It is possible touniformly light the document D along a main scanning direction of thedocument D by the light that is led by the light leading member 31 afterbeing output from the LED 32 and then output from the outputting surface31 b. Because of this, a light receiving property of a light received bya CCD 17 is improved and therefore it is possible to improve the qualityof an image formed by the printer engine 3 based on a result of readingby the image reading apparatus 13.

Furthermore, according to this embodiment, the LED 32 is simplylight-press fitted to the press-fitting concave parts 68 for the pointlight sources of the holding member 66. Hence, if a certain LED 32 doesnot work, only the LED 32 which does not work is exchanged. Hence, it isnot necessary to exchange the entirety of plural LEDs 32. It is also notnecessary to exchange the entirety of plural LEDs 32 including the lightleading member 31. Hence, the maintenance when an LED 32 does not workcan be implemented at low cost.

In addition, in the case where the holding member 66 is made of metal,it is possible to improve transferability and radiation-ability of heatgenerated by the LED 32 and the peripheral circuit element 62, so thatit is possible to prevent the performance of the LEDs 32 and theperipheral circuit element 62 from degrading due to the influence of theheat.

In this embodiment, as well as the single positioning hole 57 a of thefourth embodiment of the present invention (See FIG. 11 through FIG.13), the screw insertion hole 69, situated in the center part in thelongitudinal direction of the holding member 66 has a circular holeshaped configuration having a substantially same outside diameter as thefixing screw 71. The length along the longitudinal direction in theholding member 66 of other screw insertion hole 69 may be longer(elongated) than the diameter of the fixing screw 71. In this case, evenif a thermal expansion difference (a thermal expansion difference in thedirection along the longitudinal direction of the holding part 34 andthe holding member 66) is generated between the holding part 34 and theholding member 66 depending on the change of the temperature, ageneration of a bend of the holding part 34 or the holding member 66 dueto the thermal expansion difference can be prevented. Hence, a positiongap between the LEDs 32 and the light leading member 31 based on thebend due to a thermal expansion difference can be prevented. Because ofthis, lighting for the document D can be further uniformly done alongthe main scanning direction of the document D.

Next, the seventh embodiment of the present invention is discussed withreference to FIG. 18 and FIG. 19. FIG. 18 is an exploded perspectiveview showing a structure of the lighting device of the seventhembodiment of the present invention. FIG. 19 is a longitudinal sectionalview of the lighting device shown in FIG. 18.

In this embodiment, a lighting device 75 is provided for lighting thedocument D situated on the contact glass 12 from a lower side of thecontact glass 12. The image reading apparatus 13 (See FIG. 4) is formedby the lighting device 75 and the CCD 17 (See FIG. 4) reading areflection light (reading light) reflected by the document D after thelight output from the lighting device 75 is irradiated on the documentD.

A basic structure of the lighting device 75 is the same as the lightingdevice 65 of the sixth embodiment of the present invention. A differentpoint of the lighting device 75 from the lighting device 65 is thatplural press-fitting concave parts 76 for peripheral circuit elements,in addition to plural press-fitting concave parts 68 for the point lightsources, are formed in the holding member 66 of the lighting device 75.The LEDs 32 are light-press-fitted into the press-fitting concave parts68 for the point light sources and the peripheral circuit elements 62such as the electric current limiting resistance are light-press-fittedinto the press-fitting concave parts 76 for peripheral circuit elements.Because of this, the elements 62 are not solder-fixed to the wiringpattern 61 formed on the mounting surface 34 a of the holding part 34.

In this embodiment, as well as the sixth embodiment, the positioningpart 74 is formed by the holding part 34 having the mounting surface onwhich the wiring pattern 61 is formed and the contact standard surface72.

Under this structure, the holding member 66 holding the LEDs 32 and theperipheral circuit elements 62 is fixed to the holding part 34 where thewiring pattern 61 is formed on the mounting surface 34a, by using thefixing screws 71, so that the LEDs 32 and the peripheral circuitelements 62 are pressed and connected to the wiring pattern 61. Becauseof this, it is possible to electrically connect the LEDs 32.

The mounting surface 34 a extends in parallel with the longitudinaldirection of the light leading member 31. Hence, by mounting the holdingmember 66 light-press-fitting the LEDs 32 into the press-fitting concaveparts 68 for the point light sources on the mounting surface 34 a, it ispossible to position plural LEDs 32 and the light leading member 31 sothat the arrangement direction of the LEDs 32 is consistent with thelongitudinal direction of the light leading member 31. In addition, bycontacting the contact surface 73 of the holding member 66 with thecontact standard surface 72 of the light leading member 31, it ispossible to cause the gap between each of the LEDs 32 and the incidentsurface 31 a of the light leading member 31 to be made constant. Becauseof this, the light beams from the LEDs 32 are uniformly incident on theincident surface 31 a of the light leading member 31.

In addition, according to this embodiment, only the wiring pattern 61 isformed on the mounting surface of the holding part 34. It is notnecessary to solder-fix the elements connected to the wiring pattern 61and therefore it is possible to reduce the number of working processes.Furthermore, it is possible to eliminate the influence of heat on thelight leading member 31 at the time of solder-fixing. Therefore, it ispossible to maintain a good light leading ability of the light leadingmember 31.

Furthermore, according to this embodiment, the peripheral circuitelement 62 is simply light-press-fitted into the press-fitting concaveparts 76 of the holding member 66. Hence, if a certain peripheralcircuit element 62 does not work, only the peripheral circuit element 62which does not work is exchanged. Hence, the maintenance when theperipheral circuit element 62 does not work can be implemented at lowcost.

Next, the eighth embodiment of the present invention is discussed withreference to FIG. 20. FIG. 20 is a longitudinal sectional view of thelighting device.

In this embodiment, a lighting device 80 is provided for lighting thedocument D situated on the contact glass 12 from a lower side of thecontact glass 12. The image reading apparatus 13 (See FIG. 4) is formedby the lighting device 80 and the CCD 17 (See FIG. 4) reading areflection light (reading light) reflected by the document D after thelight output from the lighting device 80 is irradiated on the documentD.

A basic structure of the lighting device 80 is the same as the lightingdevice 65 of the sixth embodiment (See FIG. 16 and FIG. 17) and thelighting device 75 of the seventh embodiment (See FIG. 18 and FIG. 19)of the present invention. A different point of the lighting device 80from the lighting devices 65 and 75 is that a heat radiation part 81 isformed at a rear surface side of a surface of the holding member 66where the LEDs 32 and the peripheral circuit element 62 arelight-press-fitted, in the lighting device 80. The heat radiation part81 is formed in a fin-shaped state so as to be in a direction which theheat radiation part 81 extends to obliquely and upward at a positionwhere the lighting device 80 is installed in the image reading apparatus13.

In addition, in the case where the heat radiation part 81 is formed inthe holding member 66, it is possible to improve radiation-ability ofheat generated by the LED 32 and the peripheral circuit element 62, sothat it is possible to prevent the performance of the LEDs 32 and theperipheral circuit element 62 from degrading due to the influence of theheat.

Next, the ninth embodiment of the present invention is discussed withreference to FIG. 21. FIG. 21 is a longitudinal sectional view of thelighting device.

In this embodiment, a lighting device 85 is provided for lighting thedocument D situated on the contact glass 12 from a lower side of thecontact glass 12. The image reading apparatus 13 (See FIG. 4) is formedby the lighting device 85 and the CCD 17 (See FIG. 4) reading areflection light (reading light) reflected by the document D after thelight output from the lighting device 85 is irradiated on the documentD.

The lighting device 85 includes a light leading member 31, the substrate86 where the wiring pattern 61 is formed, plural LEDs 32, pluralperipheral circuit elements 62, and the holding member 66 with pluralpress-fitting concave parts 76 for peripheral circuit elements and thepress-fitting concave parts 68 for the point light sources. The LEDs 32are light-press-fitted into the press-fitting concave parts 68 for thepoint light sources so as to be held. The peripheral circuit elements 62are light-press-fitted into the press-fitting concave parts 76 forperipheral circuit element.

The holding part 34 is formed in a body at a side of the incidentsurface 31 a of the light leading member 31. The holding part 34 holdsthe substrate 86 and the holding member 66 in a state where thesubstrate 86 and the holding member 66 are stacked.

The holding part 34 extends along a longitudinal direction of the lightleading member 31. In the holding part 34, a mounting surface 34 a isformed so as to be in parallel with a longitudinal direction of thelight leading member 31 and orthogonal to the incident surface 31 a.Plural screw holes 87 are formed at positions in the holding part 34along the longitudinal direction of the holding part 34.

The substrate 86 has a linear rectangular configuration extending in adirection along a longitudinal direction of the light leading member 31so as to assemble the lighting device 85 by using this substrate 86.Plural insertion holes 88 are formed in position along the longitudinaldirection. Plural insertion holes 89 are formed in the holding member 86in position along a longitudinal direction of the light leading member31 by assembling the lighting device 85 by using this holding member 86.Positioning pins 90 are inserted into the corresponding insertion holes88 and 89. A screw part is formed in a head end part of each of thepositioning pin 90 and this screw part is screw-fixed with acorresponding screw hole 87 of the holding member 34. A positioningmember 91 causes a gap between each of the LEDs 32 arranged in a linestate and the light leading member 31 to be constant by the holding part34 having the mounting surface 34 a and the positioning pins 90. Thepositioning member 91 also causes an arrangement direction of the LEDs32 to be positioned along the longitudinal direction of the lightleading member 31.

Under this structure, the substrate 86 and the holding member 66 aremounted on the mounting surface 34 a of the holding part 34 in a statewhere the substrate 86 and the holding member 66 are stacked.Positioning pins 90 are inserted into the insertion holes 88 and 89. Thescrew part formed in the head end part of the positioning pin 90 isscrew-fixed with the screw hole 87 of the holding member 34. As a resultof this, the holding member 66 and the substrate 86 are fixed to theholding part 34. The LEDs 32 and the peripheral circuit elements 62 arepressed and connected to the wiring pattern 61 formed on the substrate86. Because of this, it is possible to electrically connect the LEDs 32to the peripheral circuit element 62.

The mounting surface 34 a extends in parallel with the longitudinaldirection of the light leading member 31. Hence, by mounting the holdingmember 66 and the substrate 66 on the mounting surface 34 a, it ispossible to position plural LEDs 32 which are light-press-fitted in thepress-fitting concave parts 68 for the point light sources of theholding member 66 and the light leading member 31 so that thearrangement direction of the LEDs 32 is consistent with the longitudinaldirection of the light leading member 31. In addition, by screw-fixingthe positioning pins 90 inserted in the insertion hole 89 of the holdingmember 66 mounted on the mounting surface 34 a and the insertion hole 88of the substrate 89 into the corresponding screw holes 87 of the holdingpart 34, it is possible to cause the gap between each of the LEDs 32which are light-press-fitted in the press-fitting concave parts 68 forthe point light sources of the holding member 66 and the incidentsurface 31 a of the light leading member 31 to be made constant. Becauseof this, the light beams from the LEDs 32 are uniformly incident on theincident surface 31 a of the light leading member 31. It is possible touniformly light the document D along a main scanning direction of thedocument D by the light that is led by the light leading member 31 afterbeing output from the LED 32 and then output from the outputting surface31 b. Because of this, a light receiving property of a light received bya CCD 17 is improved and therefore it is possible to improve the qualityof an image formed by the printer engine 3 based on a result of readingby the image reading apparatus 13.

Furthermore, according to this embodiment, since the wiring pattern 61is formed on an exclusive substrate 86, a special process for formingthe wiring pattern on the mounting surface 34 a of the holding part 34is not necessary so that productivity can be improved.

Next, the tenth embodiment of the present invention is discussed withreference to FIG. 22. FIG. 22 is a longitudinal sectional view of thelighting device.

In this embodiment, a lighting device 95 is provided for lighting thedocument D situated on the contact glass 12 from a lower side of thecontact glass 12. The image reading apparatus 13 (See FIG. 4) is formedby the lighting device 95 and the CCD 17 (See FIG. 4) reading areflection light (reading light) reflected by the document D after thelight output from the lighting device 95 is irradiated on the documentD.

A basic structure of the lighting device 95 is the same as the lightingdevice 85 of the ninth embodiment of the present invention. A differentpoint of the lighting device 95 from the lighting device 85 is that thepositioning pin 96 and the holding part 34 are formed in a body in thelighting device 95.

A screw part is formed in the head end part of the positioning pin 96.The insertion hole 88 of the substrate 86 and the insertion hole 88 ofthe holding member 66 have the positioning pin 96 inserted so that thesubstrate 86 and the holding member 66 are mounted on the mountingsurface 34 a of the holding part 34 in a state where the substrate 86and the holding member 66 are stacked. A nut 97 is screw-fixed with thescrew part of the head end part of the positioning pin 96. Byscrew-fixing the nut 97, the substrate 86 and the holding member 66 arefixed to the holding part 34.

A positioning member 98 causes a gap between each of the LEDs 32arranged in a line state and the light leading member 31 to be madeconstant by the holding part 34 having the mounting surface 34 a and thepositioning pin 96. The positioning member 98 also makes an arrangementdirection of the LEDs 32 to be positioned along the longitudinaldirection of the light leading member 31.

Under this structure, the positioning pin 96 is formed with the holdingmember 34 in a body. Hence, when the substrate 86 and the holding member66 are fixed to the holding part 34 by the positioning pin 96, it ispossible to improve positioning precision between the holding member 66and the holding part 34. Because of this, it is possible to uniformlylight the document D along a main scanning direction of the document D.Hence, a light receiving property of a light received by a CCD 17 isimproved and therefore it is possible to improve the quality of an imageformed by the printer engine 3 based on a result of reading by the imagereading apparatus 13.

The present invention is not limited to the above-discussed embodiments,but variations and modifications may be made without departing from thescope of the present invention.

This patent application is based on Japanese Priority Patent ApplicationNo. 2004-202998 filed on Jul. 9, 2004, the entire contents of which arehereby incorporated by reference.

1. An image reading apparatus, comprising: a plurality of point lightsources, arranged in a straight line state, configured to output lightto light a document; a light leading member, positioned in front in alight outputting direction of the light output from the point lightsources, configured to receive the light incident on a surface of thelight leading member, and to lead the received light so as to irradiatealong a main scanning direction toward the document; a photoelectricconversion element configured to receive reflection light from thedocument; a point light source array substrate where the point lightsources are provided in the line state; and a holding part having amounting surface extending in parallel with the longitudinal directionof the light leading member, the mounting surface being where the pointlight source array substrate is mounted, wherein the light leadingmember includes a positioning unit configured to make a gap between oneof the point light sources arranged in the line state and the lightleading member the same as a gap between another of the point lightsources and the light leading member, and to make an arrangementdirection of the point light sources be positioned along a longitudinaldirection of the light leading member.
 2. The image reading apparatus asclaimed in claim 1, wherein the positioning unit is formed by aninsertion concave part and a contact standard surface, the insertionconcave part is provided in the light leading member and extends inparallel with the longitudinal direction of the light leading member,and a contact surface formed in the substrate contacts the contactstandard surface formed deep in the insertion concave part by insertingthe substrate in the insertion concave part.
 3. The image readingapparatus as claimed in claim 1, wherein the positioning unit is formedby an insertion concave part and an incident surface of the lightleading member, the insertion concave part is provided in the lightleading member and extends in parallel with the longitudinal directionof the light leading member, and an emitting surface of each of thepoint light source contacts the incident surface by inserting thesubstrate in the insertion concave part.
 4. The image reading apparatusas claimed in claim 1, wherein the positioning unit is formed by theholding part and a plurality of installation screw holes, the holdingpart is provided in the light leading member, and the installation screwholes are formed in the holding part, face a plurality of positioningholes formed in the substrate, and have a structure where fixing screwsinserted in the positioning holes are screw-fixed with the installationscrew holes, by mounting the point light source array substrate on themounting surface.
 5. The image reading apparatus as claimed in claim 4,wherein one of a plurality of positioning holes, situated in the centerpart in the longitudinal direction in the substrate, has a circular holeshaped configuration having a substantially same outside diameter as thefixing screw, a length along the longitudinal direction in the substrateof the other positioning hole is longer than a diameter of the fixingscrew, and the length along a direction perpendicular to thelongitudinal direction in the substrate of the other positioning hole isthe substantially same as the diameter of the fixing screw.
 6. The imagereading apparatus as claimed in claim 1, wherein the positioning unit isformed by the holding part and a wiring pattern, the holding part isprovided in the light leading member, and the wiring pattern is formedon the mounting surface and is connected to the point light source. 7.The image reading apparatus as claimed in claim 1, further comprising: aholding member having a plurality of press-fitting concave parts for thepoint light sources, wherein the point light sources are press-fitted inthe press-fitting concave parts; the positioning unit is formed by theholding part and a contact standard surface, the holding part isprovided in the light leading member, a wiring pattern is formed on themounting surface, and a contact surface formed in the holding membercontacts the contact standard surface formed on the light leadingmember, by mounting the holding member having one of the point lightsources is light press fitted in the press-fitting concave part for thepoint light source on the mounting surface so that the point lightsource is connected to the wiring pattern.
 8. The image readingapparatus as claimed in claim 7, wherein a press-fitting concave partfor a peripheral circuit element where the peripheral circuit element islight-press-fitted is formed in the holding part, and the peripheralcircuit element which is light-press-fitted in the press-fitting concavepart for the peripheral circuit element is connected to the wiringpattern.
 9. The image reading apparatus as claimed in claim 7, whereinthe holding member is made of metal.
 10. The image reading apparatus asclaimed in claim 7, wherein the holding member has a heat radiationpart.
 11. The image reading apparatus as claimed in claim 1, furthercomprising: a holding member having a plurality of press-fitting concaveparts for the point light sources, the press-fitting concave parts beingparts into which the point light sources are press-fitted; and asubstrate where a wiring pattern is formed, wherein the positioning unitis formed by the holding part and a positioning pin, wherein the holdingpart is provided in the light leading member, the substrate and theholding member are stacked, the positioning pin is fixed to the holdingpart so as to pierce the substrate and the holding member for positionfixing, and the substrate is mounted on the mounting surface, in a statewhere the point light source light-press-fitted in the press-fittingconcave part is connected to the wiring pattern.
 12. The image readingapparatus as claimed in claim 11, wherein the positioning pin is formedin a body with the holding part.
 13. The image reading apparatus asclaimed in claim 1, wherein the mounting surface of the holding part isuniformly formed with the light leading member.
 14. The image readingapparatus as claimed in claim 1, wherein the mounting surface of theholding part is formed separately from the light leading member.
 15. Theimage reading apparatus as claimed in claim 1, further comprising: acontact standard surface having a structure where a contact surfaceformed in the point light source array substrate contacts the contactstandard surface by mounting the point light source array substrate onthe mounting surface.
 16. The image reading apparatus as claimed inclaim 15, wherein the holding part and the contact standard surface areformed in the light leading member.
 17. An image forming apparatus,comprising: an image reading apparatus; and a printer engine configuredto form an image on a recording medium corresponding to image data readby the image reading apparatus, wherein the image reading apparatusincludes a plurality of point light sources, arranged in a straight linestate, configured to output light to light a document; a light leadingmember, positioned in front in a light outputting direction of the lightoutput from the point light sources, configured to receive the lightincident on a surface of the light leading member and to lead thereceived light so as to irradiate along a main scanning direction towardthe document; a photoelectric conversion element configured to receivereflection light from the document; a point light source array substratewhere the point light sources are provided in the line state; and aholding part having a mounting surface extending in parallel with thelongitudinal direction of the light leading member, the mounting surfacebeing where the point light source array substrate is mounted, the lightleading member including a positioning unit configured to make a gapbetween each of the point light sources arranged in the line state andthe light leading member the same as a gap between another of the pointlight sources and the light leading member, and to make an arrangementdirection of the point light sources be positioned along a longitudinaldirection of the light leading member.
 18. The image reading apparatusas claimed in claim 17, wherein the mounting surface of the holding partis uniformly formed with the light leading member.
 19. The image readingapparatus as claimed in claim 17, wherein the mounting surface of theholding part is formed separately from the light leading member.
 20. Theimage reading apparatus as claimed in claim 17, further comprising: acontact standard surface having a structure where a contact surfaceformed in the point light source array substrate contacts the contactstandard surface by mounting the point light source array substrate onthe mounting surface.
 21. The image reading apparatus as claimed inclaim 20, wherein the holding part and the contact standard surface areformed in the light leading member.
 22. An image reading apparatus,comprising: a plurality of point light sources, arranged in a straightline state, configured to output light to light a document; leadingmeans for receiving the light incident on a surface of the leadingmeans, and for leading the received light so as to irradiate along amain scanning direction toward the document, the leading meanspositioned in front in a light outputting direction of the light outputfrom the point light sources; means for receiving reflection light fromthe document; a point light source array substrate where the point lightsources are provided in the line state; and a holding part having amounting surface extending in parallel with the longitudinal directionof the leading means, the mounting surface being where the point lightsource array substrate is mounted, wherein the leading means includespositioning means for making a gap between one of the point lightsources arranged in the line state and the leading means the same as agap between another of the point light sources and the leading means,and for making an arrangement direction of the point light sources bepositioned along a longitudinal direction of the leading means.
 23. Theimage reading apparatus as claimed in claim 22, wherein the mountingsurface of the holding part is uniformly formed with the leading means.24. The image reading apparatus as claimed in claim 22, wherein themounting surface of the holding part is formed separately from theleading means.
 25. The image reading apparatus as claimed in claim 22,further comprising: a contact standard surface having a structure wherea contact surface formed in the point light source array substratecontacts the contact standard surface by mounting the point light sourcearray substrate on the mounting surface.
 26. The image reading apparatusas claimed in claim 25, wherein the holding part and the contactstandard surface are formed in the leading means.